Update rmqamqpt_frame.cpp

Signed-off-by: Evgeny Malygin <[email protected]>

src/rmq/rmqamqpt/rmqamqpt_frame.cpp

@@ -66,19 +66,21 @@ Frame::ReturnCode Frame::decode(Frame* frame,
         return Frame::PARTIAL;
     }
 
-    bsl::memcpy(&frame->d_type, &buffer[0], sizeof(frame->d_type));
-
-    bdlb::BigEndianUint16 channel;
-    bsl::memcpy(&channel, &buffer[1], sizeof(channel));
-    frame->d_channel = channel;
-
+    // Decode payload length first to return early if Frame is not full.
     bdlb::BigEndianUint32 payloadLength;
     bsl::memcpy(&payloadLength, &buffer[3], sizeof(payloadLength));
 
-    if ((frameOverhead() + payloadLength) > bufferLen) {
+    if (bufferLen < (frameOverhead() + payloadLength)) {
         return Frame::PARTIAL;
     }
 
+    // Finally decode the skipped parts of the header.
+    bsl::memcpy(&frame->d_type, &buffer[0], sizeof(frame->d_type));
+
+    bdlb::BigEndianUint16 channel;
+    bsl::memcpy(&channel, &buffer[1], sizeof(channel));
+    frame->d_channel = channel;
+
     bsl::size_t buffer_len = frameHeaderSize() + payloadLength;
     if (buffer[buffer_len] != Constants::FRAME_END) {
         BALL_LOG_ERROR << "Decode error: expected Frame End marker. Frame: "